Peking University, May 1, 2013: Interdisciplinary journal Small published a special issue on April 22 on low-dimensional carbon materials in April as a commemorative gift for the 20th birthday of the Center for Nanochemistry (CNC) at Peking University.
The special issue contains 26 papers with one concept article, nine review articles, nine communications, and seven full papers. The content of these papers covers a broad range of low-dimensional carbon materials research, including the controlled synthesis of low-dimensional carbon materials, photochemical engineering and Raman spectroscopy of sp2 nanocarbons, and applications of carbon nanomaterials for energy storage and conversion, sensors, and field-effect transistors. As related current fascinating topics, h -BN, h -BN/ graphene hybrids, and MoS2 are also included in the special issue.
The Center for Nanochemistry (CNC) at Peking University is one of the pioneering institutions promoting the field of nanochemistry, a frontier of chemistry aimed at discovering materials and structures at the nanometer scale and exploring dimensionality effects on chemical systems.
As its antecedent, the nanochemistry laboratory was initiated by Professor Liu Zhongfan in early June of 1993. Since then, the CNC has gone through a 20 year innovative journey with numerous exciting achievements: the CNC has been the incubator of the nanochemistry curricula for graduate students at Peking University since 2002, the CNC has held the Nanochemistry Symposia in the Annual Meeting of the Chinese Chemical Society (CCS) since 2004, and established the Chinese Nanochemistry Society in 2013 as a new branch of the CCS.
The broad research activities at the CNC cover self-assembly systems, surface-enhanced Raman spectroscopy (SERS), tip chemistry, nanoelectronics and molecular electronics, as well as low-dimensional carbon materials such as carbon nanotubes, graphene, and graphyne, which has been one of the CNC’s particular favorites over the last one and a half decades.
The first pioneering contribution of the CNC to nanocarbon research was the chemical self-assembly of carbon nanotubes on solid surfaces. Inspired by the self-assembly of small organic molecules, the CNC reported the first self-assembly of “giant” one-dimensional, single-walled carbon nanotubes (SWNTs) on gold substrates in 2000. The CNC methodology developed for self-assembly on various solid substrates has since been widely used in carbon nanotube-based nanoelectrochemistry, chemical sensors, and functional devices.
The CNC has been one of the representative institutions working on the controlled growth of single-walled carbon nanotubes. Using a chemical vapor deposition (CVD) furnace, CNC chemists have made fantastic progress toward the structural control of SWNTs. Well-known achievements include chirality-cloning growth and diameter-designed growth using sp2 carbon catalysts, based on a novel “VS” growth model. Using chemically tailored smart tapes, the pristine surface-grown SWNTs can be perfectly separated into “metallic” and “semiconducting” arrays, opening a practical pathway for carbon nanotube electronics.
In early 2008, the CNC barged into the graphene world. Profiting from its strong CVD experience, the CNC team quickly demonstrated its abilities on the controlled growth of two dimensional graphene and its hybrid materials, as evidenced by a number of innovative growth methods such as strict monolayer growth via synergistic bimetal alloys, bilayer growth via van der Waals epitaxy, mosaic graphene via a two-step grafting growth, segregation-only growth, wrinkle engineering, etc.
Another adventure and contribution of the CNC to this stimulating area is the photochemical engineering of graphene. Using photogenerated free radicals, the CNC has achieved the high-efficiency chemical modification of inert graphene. Examples include photochlorination, photomethylation, photocatalytic oxidation, and Janus graphene.
Raman spectroscopy of low-dimensional carbon materials is another research focus of the CNC team. Using resonant Raman spectroscopy, the CNC team has demonstrated that resonant Raman spectra of SWNTs depend on the strain type and that the strain can affect/modulate the geometric structure of SWNTs, indicating that Raman spectroscopy is a powerful and useful tool for the study and characterization of strain in SWNTs. The CNC team also used graphene to open up a unique platform for SERS studies, in which graphene can be used as a flat substrate for SERS and can improve the SERS performance.
In addition to this fundamental interest in nanocarbons, the CNC has also devoted itself to molecular/nanoelectronic devices and biosensors. Supported by this strong carbon materials research, the CNC team has developed universal methodologies to create reliable molecular devices based on point contacts formed from carbon nanotubes or graphene through covalent amide linkages. A unique feature of these devices is that they consist of only one or two molecules as conductive elements. This implies a great potential for future applications in ultrasensitive biosensors and accurate molecular diagnostics.
Written by: Guo Caichen
Edited by: Zhao Ning, Zhang Jiang
Source: Small & PKU News (Chinese)
